"To me, this is bigger than football and it would be selfish on my part to look the other way," Kaepernick told reporters. "There are bodies in the street and people getting paid leave and getting away with murder."

Harbaugh coached Kaepernick in San Francisco for four seasons until leaving for the Michigan job last year. Harbaugh benched Alex Smith in favor of Kaepernick in 2012, which gave the quarterback his opportunity to rise to a higher profile in the NFL.

Harbaugh's brother -- Baltimore Ravens coach John Harbaugh -- said Monday that he respected Kaepernick's right to protest, even if he doesn't agree with how he's doing it.

"Voltaire so eloquently stated, 'I may not agree with what you say, but I'll defend it until death your right to say it,'" John Harbaugh said. "That's a principle that our country is founded on. I don't think you cannot deny someone the right to speak out or mock or make fun or belittle anybody else's opinion."

John Harbaugh, however, said it's a fine line between standing up for what you believe in and not becoming a distraction to the team. He tells his players that you have to make sure you believe what you say publicly because you have to own it.

"You respect our team, our organization and the other players," John Harbaugh said. "You respect the mission that we're on and what we're trying to accomplish. None of us ever want us to detract or disrespect the efforts of all the other players on the football team. That's the balance that all of us have to strike when we speak out about something like that."